Science Round-up: Summer Updates

According to the Proceedings of the National Academy of Sciences, probiotic bacteria may lessen anxiety and depression. Research carried out at the Alimentary Pharmabiotic Center in University College Cork has unearthed remarkable evidence that these bacteria have the potential to alter brain neurochemistry, simultaneously highlighting the importance of communication between the gut and the brain.

The study observed that mice fed with the bacteria Lactobacillus rhamnosus JB-1 exhibited a significant decrease in behaviours related to stress, anxiety and depression compared to those fed with only broth. Furthermore, lower levels of the stress induced hormone corticosterone were found. Regular feeding with the bacterial strain resulted in changes in the expression of receptors for the neurotransmitter GABA in the mouse brain, indicating the direct effect of probiotics on brain chemistry. John F. Cryan, senior author on the publication said of the research: “These findings […] open up the intriguing opportunity of developing unique microbial-based strategies for treatment for stress-related psychiatric disorders such as anxiety and depression”

While speculation as to the consequences of this research should be cautious, as the study is limited to the effect of probiotics on mice brain chemistry, it is interesting to consider how common phrases like having “gut feelings” might be more than metaphors.

Earth’s Antimatter

In the August issue of The Astrophysical Journal, it was publicised that a thin band of antimatter particles encircling the earth had been observed by the Pamela satellite. The research team discovered that a small number of antiprotons were trapped between Earth’s Van Allen belts –belts of energetic charged particles called plasma held in place by the Earth’s magnetic field.

The Pamela (short for Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics) satellite was launched in 2006, its purpose to study the nature of cosmic rays and their composite high energy particles which smash into the Earth. When the satellite passes through a region where the inner Van Allen radiation belt is nearest to the Earth’s surface, called the South Atlantic Anomaly, it observes a far greater number of antiprotons than expected -thousands of times more than could be produced from normal particle decays.

The research team suggests that this provides evidence the antiprotons are held in bands analogous to the Van Allen belts, until such a time as they collide with the normal matter of the atmosphere, when they “annihilate” in a flash of light energy. The discovery of these anti-matter particles could bring physicists nearer to being able to utilize them for a variety of medical and fuel applications. Most significantly, a Nasa-founded study by Draper Laboratory described how miniscule masses of antiprotons could be used as fuel for spacecraft.

First Step to Curbing Malaria?

Research published in the Proceedings of the National Academy of Sciences indicates that an important first step towards reducing the size of mosquito populations may have been made. Scientists have successfully created spermless male Anopheles gambiae mosquitos, the species complex which is the most efficient vector of malaria. The disease is widespread, killing around one million people in Africa alone every year, and is responsible for one in five childhood deaths.

Insect sterilization is not a new technique; exposing insects to radiation in order to make them sterile has been used successfully against the tropical screwworm and tsetse fly. But in the past, exposure to radiation left the mosquitos too weak to mate with the females. Now, mosquito embryos can be injected with tiny fragments of RNA which turn off the gene which is responsible for normal sperm development.

Extensive research using this approach was carried out by Imperial College London’s Dr Catteruccia and her team. They observed that female mosquitos were equally willing to mate with infertile mosquitos as they were with fertile ones. Female mosquitos mate only once in their lives, and so in principal, by introducing these sterile males to the population you can gradually reduce the number of hatching mosquitos. Despite this positive result, Dr Catteruccia warns that this research only a proof of principal. The process of creating and introducing the males into the populations is currently too labour intensive to be effective.